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Allergic Colitis

  • Many babies are fussy eaters, but some are much more so than others. If your baby seems constantly irritable, has problems feeding (she has difficulty keeping food down and/or doesn’t want to eat) or has excessive gassiness, diarrhea and/or blood in his stools, he may be allergic to proteins in cow’s milk. This condition, which only affects babies, is called allergic colitis. The good news is that for the vast majority of children, it is just temporary.

    In allergic colitis, the milk proteins cause a reaction within your baby’s body that irritates his colon (large intestine) and creates small ulcerations in its lining. If left untreated, it can lead to serious problems, so it’s important to diagnose and treat it early. Fortunately, once identified, allergic colitis is quite easy to treat.

    • Allergic colitis is also sometimes called “cow’s milk protein allergy (CMPA)” or “milk protein allergy.”

    • Two to three percent of infants have this condition.

    • While symptoms may appear until a baby turns 6 months old, most babies show signs within the first two months of life. In most babies, the symptoms start off mild and gradually worsen.

    • Allergic colitis is treated by removing the protein from your baby’s diet, and it usually disappears by the time the child turns 1.

    • Medication can help your baby’s reflux until she outgrows it.

    How Boston Children's Hospital approaches allergic colitis

    At Children’s, we treat babies with allergic colitis through our Division of Gastroenterology, Hepatology and Nutrition.  We’ve been treating children with GI conditions like allergic colitis for more than 65 years, and we’ve successfully cared for some of the most complex cases.

    Our specialty programs offer innovative care not available at other hospitals for children with chronic gastrointestinal and nutritional problems. We offer a full range of diagnostic and therapeutic procedures and have a state-of-the-art endoscopy and motility unit. Whether your child’s allergic colitis is mild or severe, you’re in good hands with us. Call 617-355-6058 for an appointment.

    Allergic colitis: Reviewed by Elizabeth Hait, MD, MPH
    © Children’s Hospital Boston, 2010

    Contact Us

    Boston Children's Hospital
    300 Longwood Avenue
    Boston MA 02115

  • We’ve provided some answers to those questions here, and when you meet with our experts, we can talk with you more about your child’s diagnosis and treatment.

    What is allergic colitis?

    Allergic colitis is a condition in which your baby’s immune system overreacts to the proteins found in cow’s milk, leading to inflammation and ulcerations (tiny breaks in the skin) in his colon (large intestine). Babies differ in how sensitive they are to milk. Some have very few symptoms, and others might experience blood in the stools if a breastfeeding mother has even a small splash of milk in her morning coffee.

    Who is at risk for allergic colitis?

    Allergic colitis isn’t uncommon — it affects between two and three percent of infants. Babies from families with a history of food allergies, asthma and/or environmental allergies seem to have a slightly higher risk of developing the condition.

    Why is it a concern?

    Allergic colitis can make eating very uncomfortable for your baby, so he may not get the nutrition he needs. In extremely rare cases, the intestine may get so swollen that food is unable to pass through it, or the lining of the intestine may become so inflamed that it’s unable to absorb nutrients. If this is the case with your baby, he may need to be fed intravenously (through an IV) until his intestine has had time to heal.

    What complications are associated with allergic colitis?

    Between ages 4 and 6 months, many babies go through a period of reflux (spitting up food), but babies with allergic colitis may have an especially hard time with reflux. This means that even though you are following a dietitian’s recommendations about how to feed your baby with allergic colitis as instructed, she may still become irritable. This doesn’t mean that her allergic reactions are back.

    Medication can help your baby’s reflux until he outgrows it. This usually happens by the time he can sit up by himself, around the time he’s 7 months old.

    Should I delay introducing solid foods to my child’s diet?

    Not at all. Introduce solid foods just as you normally would, when your child is between 4 and 6 months old. Introducing solid foods is important because it lets your baby’s body:

    • become accustomed to new foods
    • reap the benefits of a wide variety of vitamins and minerals such as zinc and iron, found in cereal, but not in high concentrations in either breast milk or formula

    Tips on introducing solid food to your child’s diet

    1. Remember to read the ingredients on the label of all baby food you buy to make sure that there’s no milk or soy (as appropriate). Make sure to do this each time you buy the food, since the recipes may change, even with your favorite brands.

    2. Introduce new foods first thing in the morning, so you can watch for an allergic reaction such as diarrhea, vomiting, rash or irritability.

    3. Introduce only one new food every three to five days, so that if your baby has a delayed allergic reaction, you know which food caused it.


    What causes allergic colitis?

    Allergic colitis seems to be caused by a combination of changes to the mother’s immune system during pregnancy, and the immaturity of a baby’s own immune system. But it’s not yet known why some babies develop the condition and others don’t.

    There may be a hereditary component, since babies who come from families with a history of food allergies, asthma or environmental allergies seem to be more likely to have allergic colitis.


    What are the symptoms of allergic colitis?

    Most often, a baby with allergic colitis seems extremely fussy, difficult to console and has bloody stools. Some infants also have diarrhea and vomiting, and some may show other signs of allergies, such as nasal congestion or eczema. It’s important to remember that allergic colitis falls on a spectrum – some babies are much more sensitive to milk protein (and have much more severe symptoms) than others.


    Q: How do I know if my child has allergic colitis and if I should take her to a doctor?

    A: If your baby is extremely irritable, and you notice vomiting and gassiness, it’s a good idea to make an appointment to see his pediatrician. Blood in the stool is a sure sign that you should take your baby to see his doctor, who can then refer you to a pediatric gastroenterologist if it’s appropriate. Ultimately, you know your child best, and shouldn’t hesitate to contact your health care provider with any concern.

    Q: Will my child be all right?

    A: Yes. Allergic colitis is easily treated by removing the offending proteins from your baby’s diet.

    Q: How is allergic colitis different from a milk allergy?

    A: Allergic colitis is a kind of milk allergy.  But it doesn’t cause the same severe, immediate, life-threatening reaction that “regular” milk allergies cause.

    Q: Is the condition ever life-threatening?

    A: Only in very rare and extremely severe cases may allergic colitis be life-threatening.

    Q: Will my child outgrow his allergy?

    A: Most likely. The overwhelming majority of babies with allergic colitis outgrow their milk allergy by the time they’re 1 year old.

    Q: Is my child more likely to develop other food allergies or gastrointestinal problems because she has allergic colitis?

    A: Since infants with allergic colitis are more likely to come from families with food and/or environmental allergies, they have the same hereditary risks of future allergies that all children born to that family would have. But there’s nothing about having had allergic colitis that makes your baby more or less likely to develop another allergy or any gastrointestinal disorder.

    Q: Could my child’s symptoms indicate an inflammatory bowel disorder (IBD) or irritable bowel syndrome (IBS)?

    A: No. This is an understandable question, but at this age, children are too young to show any signs of either IBD or IBS — even if one or both parents have the condition.

    Q: Should I delay introducing solid foods to my child’s diet?

    A: Not at all. Introduce solid foods just as you normally would, when your baby is between 4 and 6 months old.

    Q: Could something have happened during pregnancy to cause my baby’s allergy?

    A: No. We don’t know exactly what causes allergic colitis, but we don’t think that it’s related to anything the mother did or didn’t do during her pregnancy.

  • If your baby is fussy, irritable and resists feeding, we understand how concerned you must be. But we view a diagnosis of with allergic colitis as the first step in restoring your child to good health.

    The first thing we’ll do is check for blood in your baby’s stool. There might be blood that can only be seen through a microscope, so your child’s doctor will look for this, too. If blood is found, the symptoms are most likely caused by an allergic reaction, so we put the mother on a dairy-free diet if she’s breastfeeding, or recommend a hypoallergenic formula.

    If your baby’s symptoms don’t improve after you’ve made these dietary changes, we’ll test your baby’s stool for the presence of an infection. We may also do a flexible sigmoidoscopy, which is  a procedure that lets the doctor look inside your baby’s intestinal tract to see if there might be a polyp or an abnormal blood vessel close to the surface that could be causing the bleeding. A rectal fissure (a small tear in your baby’s skin near his rectum) could also be causing the bleeding.

    After we examine your baby and complete any necessary tests, we’ll meet with you and your family to discuss the results and the best way to proceed.

  • Most of the time, when an infant has blood in his stool, it's caused by a milk allergy. This is very treatable: We simply have the mother go on a dairy-free diet (if she's breastfeeding) or switch to a hypoallergenic formula. It takes about 72 hours for the mother's breast milk to become free of milk protein, so until you're ready to nurse again, your baby will be given a hypoallergenic formula.

    Roughly 30 percent of babies who are allergic to cow's milk protein are also allergic to soy protein, so if your baby's symptoms don't clear up, we recommend that a nursing mother avoid soy as well as dairy (or use a soy-free formula). Many moms feel nervous about this, but our registered dieticians provide lots of suggestions about how to make this as easy as possible.

    Keep in mind that even if your baby is no longer ingesting the proteins that are causing reactions in his intestine, his intestines still need to heal. That's why you may continue to notice blood in his stool for three to four weeks after starting a milk/soy-free diet. But you should notice that your infant seems to be feeling better — less irritable and less reluctant to feed. He may also seem to be putting on weight, which is also a good sign.

    Between ages 4 and 6 months, many babies go through a period of reflux (spitting up food), but babies with allergic colitis may have an especially hard time with reflux. This means that even though you are following a dietitian's recommendations about how to feed your baby with allergic colitis as instructed, she may still become irritable. This doesn't mean that her allergic reactions are back.

    Medication can help your baby's reflux until he outgrows it. This usually happens by the time he can sit up by himself, around the time he's 7 months old.

    Follow up

    Generally, we see children with allergic colitis twice after their diagnosis, to monitor their weight and nutritional intake:

    • when the baby is starting solid foods, and again around 11 months
    • when your baby is around 11 months old, and it's time to do a milk trial to see if he's outgrown the allergy.
  • Boston Children’s Hospital is home to the world’s most extensive research enterprise at a pediatric hospital. We also have many partnerships with research, biotech and health care organizations, and we work together to find innovative ways to improve kids’ health.

    Food allergy reactions are of increasing concern in the United States. About one fourth of all American households face restrictions in their diet due to a family member suffering from food allergies. Children appear particularly susceptible when dissecting the age group of peanut butter and cow milk allergic individuals. Research led by Children’s investigator Edda Fiebiger, PhD, hopes to define new strategies for diagnosis and treatment of children with allergic colitis and other food allergies.

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